Adding regions to state machine diagrams

In UML state machine diagrams, a region is a container inside a state that can hold states, pseudostates, and transitions, which you can add to state machines or states. You can use regions to define nested states and transitions. Regions allow you to provide more detail about the internal transitions of a particular state.

Before you begin

Before you can add a region to a state machine or state, you must have a UML modeling project open in the Modeling perspective.


In the diagram editor, right-click a state or state machine; then click Add UML > Region.


Tip: You can create a subdiagram of a region to help further represent a densely populated or deeply nested region. To create a subdiagram, of a region, double-click a simple or composite state and accept the prompt. The subdiagram is mapped to the state and displays its name. The parent state displays an icon to indicate the subdiagram exists.